The transmission of measurement data from a moving system to a base station that is stationary in a working space is often difficult since it is often impossible to run cables or these may break easily because of the continuous movement. As said moving systems are considered rotating or turning systems but also those performing a back-and-forth translational motion while said motion always occurs within the work space, such as for example a robot which constantly moves back and forth with an arm to perform a task. Systems that move away in one direction such as vehicles or persons on the way and moving away from a work space are not considered by the present invention but only those for which the motion occurs in a defined area, especially within the work space. In particular, systems are taken into account the movements of which are defined and predetermined.
Thus, the systems considered herein may move relative to the base station, however, they may not significantly change their distance to the base station. Besides methods for transmission using sliding contacts in rotating systems transmission using telemetry has proven particularly effective. Examples of applications are rotating tool systems in which, for example, the cutting force of a cutting edge is to be determined, turbines, rollers or vehicle wheels. While in most applications the base stations are arranged in a work space which itself is stationary, the work space may also be a combination of vehicles for the determination of the wheel forces of vehicle wheels. Although the base stations are moving during a measurement, they are stationary within their respective work area. Therefore, the base stations in this example do not perform the same motion as do the corresponding measurement units.
A known measuring device of the type explained above is described in EP1323495. This document describes a method for monitoring tools on a spindle by means of a sensor device wherein the captured measurement data are transferred in a contactless manner to a stator which forwards them to a main processor. In addition, range changes can be carried out at the sensor device by sending appropriate commands in a contactless manner from the main processor via the stator to a microprocessor of the sensor device.
A disadvantage of the arrangement described above is the fact that contactless transmission is performed by means of near field telemetry. For this purpose, it is necessary to arrange a stator in each case in the close vicinity, i.e. at a distance of a few millimeters. In many systems, in particular with rotating tools and robots employed in material machining or in assembly in industrial companies, for example, this has proven disadvantageous.